Wise Young
10-22-2006, 01:43 PM
This approach to travel, assuming that one can build a tunnel through the center of the earth, would take relatively little energy (just enough to counteract friction). Of course, building the tunnel would be a challenge. In the comments that followed this article, some people have suggested that it would be impossible since parts of the earth move relative to each other. Others point out the the debris from the tunnel could be as much as the equivalent of 35,000 Mt. Everests. Other suggested that this may be a viable concept for smaller bodies, such as the moon.
On the other hand, it is an exercise in creativity and how to think outside of the box or, in the case, outside of "the hole".
• Why must the hole go through the core of the earth? Why not build a tunnel that is a chord (from one part of the circumference to the other)? While you may not get all the benefits of gravitational acceleration to the center of the earth, you would still be able to use some of the gravitional acceleration to save energy.
• Why do we need a big tunnel? If we are not transporting humans or big objects, it can be quite small (such as a fiber optic). By the way, apparently the Russians actually created a drilling device that drilled a nine-inch diameter hole 7.5 miles into the earth's crust, as described in The Deepest Hole (http://www.damninteresting.com/?p=567). Suppose that we just set a drilling robot that could drag a cable that would provide it with power, lubricant (to wash out the contents of the hole, and a fiberoptic cable. We can pass light, x-rays, or even gamma rays through the cable.
• Do we really have to have a straight tunnel? A straight tunnel would perhaps produce the least amount of friction but, if what we are passing through the tunnel is energy, the energy could be bent around curves. Recently, Professor Eugene Polzik and his team at the Niels Bohr Institute in Copenhagen succeeded in quantum teleportation of a macroscopic object that contained several trillion atoms (Source (http://northernstar.info/articles/?id=33782)). So, maybe someday, it will be "Beam me down, Scottie" instead of "Beam me up..."
Just some random thoughts that occurred to me when I read this article.
http://www.damninteresting.com/?p=696
The Gravity Express
Posted by Alan Bellows on October 15th, 2006 at 11:22 pm
A forty-two minute gravity train route from New York City to HawaiiA forty-two minute gravity train route from New York City to HawaiiAbout four hundred years ago– sometime in the latter half of the 17th century– Isaac Newton received a letter from the brilliant British scientist and inventor Robert Hooke. In this letter, Hooke outlined the mathematics governing how objects might fall if dropped through hypothetical tunnels drilled through the Earth at varying angles. Though it seems that Hooke was mostly interested in the physics of the thought experiment, an improbable yet intriguing idea fell out of the data: a dizzyingly fast transportation system.
Hooke's calculations showed that if the technology could be developed to bore such holes through the Earth, a vehicle with sufficiently reduced friction could use such a tunnel to travel to another point anywhere on the on Earth within three quarters of an hour, regardless of distance. Even more amazingly, the vehicle would require negligible fuel. The concept is known as the Gravity Train, and though it seems inconceivably difficult to construct, it has received some serious scientific attention and research in the intervening centuries.
The basic concept behind the gravity train is straightforward: At each end of the tunnel, an observer looking into the hole would see a downhill slope. If a train at one end of the tunnel were to release its brakes, the force of gravity would immediately pull the train downhill and cause the train to accelerate much like a roller coaster. Steeper slopes would result in more speed, with the highest acceleration occurring in the straight-down tunnels which cross the Earth's center. The train would continue to accelerate until reaching the halfway point, at which time its inertia would be at odds with gravity and it would begin to decelerate. As Hooke's data indicates, if the train operated in a frictionless environment it would reach the surface on the opposite end of the tunnel at the exact moment that its speed reached zero. Naturally, a gravity train operating in a real-world environment would need to bring along enough horsepower to make up the friction loss.
One interesting property of the Gravity Express is that its transit time would always be very, very close to forty-two minutes regardless of the distance travelled. In fact, if the Earth were a perfect sphere, the trip time would always be exactly forty-two minutes and twelve seconds. Greater distances would be traversed in the same amount of time as short ones because the train's maximum speed would be increased enough to exactly make up the difference. Due to nature of gravity, this forty-two minute trip time would be consistent for any size of vehicle.
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On the other hand, it is an exercise in creativity and how to think outside of the box or, in the case, outside of "the hole".
• Why must the hole go through the core of the earth? Why not build a tunnel that is a chord (from one part of the circumference to the other)? While you may not get all the benefits of gravitational acceleration to the center of the earth, you would still be able to use some of the gravitional acceleration to save energy.
• Why do we need a big tunnel? If we are not transporting humans or big objects, it can be quite small (such as a fiber optic). By the way, apparently the Russians actually created a drilling device that drilled a nine-inch diameter hole 7.5 miles into the earth's crust, as described in The Deepest Hole (http://www.damninteresting.com/?p=567). Suppose that we just set a drilling robot that could drag a cable that would provide it with power, lubricant (to wash out the contents of the hole, and a fiberoptic cable. We can pass light, x-rays, or even gamma rays through the cable.
• Do we really have to have a straight tunnel? A straight tunnel would perhaps produce the least amount of friction but, if what we are passing through the tunnel is energy, the energy could be bent around curves. Recently, Professor Eugene Polzik and his team at the Niels Bohr Institute in Copenhagen succeeded in quantum teleportation of a macroscopic object that contained several trillion atoms (Source (http://northernstar.info/articles/?id=33782)). So, maybe someday, it will be "Beam me down, Scottie" instead of "Beam me up..."
Just some random thoughts that occurred to me when I read this article.
http://www.damninteresting.com/?p=696
The Gravity Express
Posted by Alan Bellows on October 15th, 2006 at 11:22 pm
A forty-two minute gravity train route from New York City to HawaiiA forty-two minute gravity train route from New York City to HawaiiAbout four hundred years ago– sometime in the latter half of the 17th century– Isaac Newton received a letter from the brilliant British scientist and inventor Robert Hooke. In this letter, Hooke outlined the mathematics governing how objects might fall if dropped through hypothetical tunnels drilled through the Earth at varying angles. Though it seems that Hooke was mostly interested in the physics of the thought experiment, an improbable yet intriguing idea fell out of the data: a dizzyingly fast transportation system.
Hooke's calculations showed that if the technology could be developed to bore such holes through the Earth, a vehicle with sufficiently reduced friction could use such a tunnel to travel to another point anywhere on the on Earth within three quarters of an hour, regardless of distance. Even more amazingly, the vehicle would require negligible fuel. The concept is known as the Gravity Train, and though it seems inconceivably difficult to construct, it has received some serious scientific attention and research in the intervening centuries.
The basic concept behind the gravity train is straightforward: At each end of the tunnel, an observer looking into the hole would see a downhill slope. If a train at one end of the tunnel were to release its brakes, the force of gravity would immediately pull the train downhill and cause the train to accelerate much like a roller coaster. Steeper slopes would result in more speed, with the highest acceleration occurring in the straight-down tunnels which cross the Earth's center. The train would continue to accelerate until reaching the halfway point, at which time its inertia would be at odds with gravity and it would begin to decelerate. As Hooke's data indicates, if the train operated in a frictionless environment it would reach the surface on the opposite end of the tunnel at the exact moment that its speed reached zero. Naturally, a gravity train operating in a real-world environment would need to bring along enough horsepower to make up the friction loss.
One interesting property of the Gravity Express is that its transit time would always be very, very close to forty-two minutes regardless of the distance travelled. In fact, if the Earth were a perfect sphere, the trip time would always be exactly forty-two minutes and twelve seconds. Greater distances would be traversed in the same amount of time as short ones because the train's maximum speed would be increased enough to exactly make up the difference. Due to nature of gravity, this forty-two minute trip time would be consistent for any size of vehicle.
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